The invention relates to an adjustable spindle for rotating round elastomeric objects. Specifically, the invention relates to changing the camber angle of a spindle used for rotating tires.
In the automotive industry, some manufacturers design their vehicles having a suspension which provides a camber to the wheels that are used on the vehicle. When developing tires for such vehicles, it is important to test an experimental tire under conditions very similar to those encountered on a vehicle. Accordingly, spindles used for spinning tires on test equipment have been adapted to provide camber to a tire during dynamic testing.
In prior art testing equipment, however, spindles providing a camber were not adjustable and could be set up only at one angle. Conversion to a different angle was possible but involved dismantling the equipment to change the angle. Even then, only a limited number of angles were possible.
Vehicle manufacturers often experiment with different camber angles on vehicles, and a large variety of vehicles are being manufactured with camber angle on the suspension systems, and it is important that tires be tested at the large number of camber angles which are used, or are considered experimentally.
It is an object of the present invention to provide an adjustable spindle which makes possible the quick adjustment of the camber angle of the spindle.
A spindle assembly (10) for rotating round objects comprises a spindle (12) and a spindle plate (14) attached to a back plate (16), the spindle plate (14) and back plate (16) having interposed there between at least two wedge rings (18,20), wedge rings(18,20) having a wider portion (22,22a) and a narrower portion (24,24a). In the assembly, when a narrower portion (24) of wedge ring (18) is adjacent to wider portion (22a) of wedge ring (20), an axis (26) of the spindle (12) is normal to the plane (28) of the back plate (16). The assembly (10) is adapted to vary the angle of an axis (26) of the spindle (12) relative to a plane (28) of the back plate (16) by rotating said at least two wedge rings (18,20) relative to each other and to said back plate (16).
Washers (32) used with bolts (30), and nuts (34) on the bolts (30) have a portion of a sphere (54) to accommodate a plurality of angles.
The at least two wedge rings (18,20) are adapted to interlock with each other circumferentially, permitting rotation relative to one another while maintaining their circumferential relationship to the back plate (16). The at least two wedge rings (18,20) each have an outside surface (40,40a) corresponding to its outside diameter and an inside surface (41,41a) corresponding to its inside diameter, and a back plate side (44,44a) oriented toward the back plate (16) and a spindle plate side (46,46a) oriented toward the spindle (12), and in the spindle assembly (10) in a wedge ring (18) closest to the back plate (16) the back plate side (44) forms a ninety degree (90xc2x0) angle with the outside surface (40), and in a wedge ring (20) closest to the spindle plate (14) the spindle plate side (46a) forms a ninety degree angle with the outside surface (40a).
The at least two wedge rings (18,20) are marked with indicia (48,48a) whereby the angle of the axis (26) of the spindle (12) relative to a plane (28) of the back plate (16) can be determined by the indicia.
In one embodiment, the back plate (16) and spindle plate (14) are attached to each other by a plurality of bolts (30), and the at least two interposed wedge rings (18,20) are free to rotate relative to the spindle plate (14) and the back plate (16) when the bolts (30) are not tightened. In a second embodiment, bearings (56) are interposed between spindle plate (14) and a wedge ring (20), and between wedge ring (20) and wedge ring (18), and between wedge ring (18) and back plate (16) and a pinion gear (67) is associated with the wedge rings (18,20) for rotating the wedge rings.
Also provided is a method for varying the camber angle of a spindle (12) having a spindle plate (14), comprising the steps of interposing at least two wedge rings (18,20) between a spindle plate (14) and a back plate (16) in a spindle assembly (10), wherein at least two of the at least two wedge rings (18,20) have a wider portion (22,22a) and a narrower portion (24,24a).
The method may comprise the further steps of (a) releasing tension between a back plate (16) and a spindle plate (14) in a spindle assembly, and (b) rotating at least two of the at least two wedge rings (18,20) independent of each other and the back plate (16), or the further steps of (a) associating a pinion gear (67) with the wedge rings (18,20), and (b) using the pinion gear (67) to change the angle of spindle (12).
The method may comprise the further step of providing indicia (48,48a) on at least two of the at least two wedge rings (18,20) whereby the exact angle of an axis (26) of the spindle (12) relative to a plane (28) of the back plate (16) can be determined from the indicia.